forked from DecentralizedClimateFoundation/DCIPs
87 lines
2.7 KiB
Markdown
87 lines
2.7 KiB
Markdown
---
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eip: 3978
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title: Gas refunds on reverts
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description: Reprice reverted SSTORE/CREATE/SELFDESTRUCT/LOGX operations gas via gas refund mechanism
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author: Anton Bukov (@k06a), Mikhail Melnik (@ZumZoom)
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discussions-to: https://ethereum-magicians.org/t/eip-3978-gas-refunds-on-reverts/7071/
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status: Stagnant
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type: Standards Track
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category: Core
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created: 2021-09-16
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updated: 2022-02-14
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requires: 2929
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---
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## Abstract
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For reverted state modification operations, keep access cost, but refund modification cost.
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## Motivation
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Reverting a transaction, or any of its sub-calls, drops any state modifications that happened inside.
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But now, users are being charged for the dropped modifications as if they persisted.
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Since [EIP-3298](./eip-3298.md), the gas refund mechanism works for storage restores only inside the same transaction. But on revert, the gas refund is not increased; it is completely erased.
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It can even be cheaper to transfer tokens back at the end of a transaction instead of reverting, to keep the existing gas refund.
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This should be changed.
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- Reverted SSTORE deserves to be repriced to SLOAD gas (100 gas)
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- Reverted LOG0, LOG1, LOG2, LOG3 and LOG4 deserve to be repriced to 100 gas
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- Reverted CALL with value (`positive_value_cost` = 9,000 gas) deserves to be repriced to 100 gas
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- Reverted CALL with value and account creation (`value_to_empty_account_cost` = 25,000 gas) deserves to be repriced to 100 gas
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- Reverted CREATE and CREATE2 (32,000 gas) deserve to be repriced to 100 gas
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- Reverted SELFDESTRUCT (5,000 or 25,000 gas) deserves to be repriced to 100 gas
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Moreover, it seems fair to charge CREATE and CREATE2 operations 32,000 fix price conditionally only if returned bytecode is not empty.
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## Specification
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For each callframe, track `revert_gas_refund`, initially 0.
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The set of operations that modify `revert_gas_refund` are:
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- SSTORE
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- LOG0, LOG1, LOG2, LOG3, LOG4
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- CALL
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- CREATE, CREATE2
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- SELFDESTRUCT
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They increase `revert_gas_refund` as follows:
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```javascript
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call.revert_gas_refund += operation.gas - WARM_STORAGE_READ_COST
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```
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And in case of revert let's use this value instead of just erasing `gas_refund`:
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```javascript
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if (call.reverted) {
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// existing behavior
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tx.gas_refund -= call.gas_refund;
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// New behavior added to existing according to the EIP-3978
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tx.gas_refund += call.revert_gas_refund;
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}
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```
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## Rationale
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Gas should reflect the cost of use.
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The revert cost reflects the cost of access during execution, but not the cost of modification.
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## Backwards Compatibility
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No known backward incompatibilities.
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## Test Cases
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TBD
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## Reference Implementation
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TBD
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## Security Considerations
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TBD
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## Copyright
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Copyright and related rights waived via [CC0](../LICENSE.md).
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